Due to favorable electrical characteristics, especially high breakdown voltage per length, GaN is a promising material for power transistors. The most common realization of GaN based devices is the high electron mobility transistor (HEMT). HEMTs however suffer from inferior reliability compared to their silicon counterparts. Particularly, the gate of an HEMT is vulnerable to overvoltage conditions e.g. caused by bad circuit layout or ESD (electrostatic discharge) damage. Conventional HEMTs do not have a gate protected against overvoltage conditions. Instead, conventional HEMTs must limit the maximum gate voltage to very low values and rely on good circuit design so that the device is not damaged during use, limiting the application of conventional HEMTs.